Recently, in industrial fields, robot apparatuses are being used widely to perform work more accurately and more quickly. The driving portion of a robot apparatus may be made of a multi-link structure in which multiple links are joined to each other by joints (for example, an arm unit), and by controlling rotational driving in the multiple joints, the driving of the multi-link structure as a whole is controlled.
At this point, when performing work on a target object with a robot apparatus, information about the position and the orientation of the target object is acquired by an imaging device provided in the robot apparatus, and the multi-link structure is driven based on the information about the position and the orientation. For example, Patent Literature 1 discloses technology for a robot apparatus equipped with an arm unit having a gripping mechanism and imaging means provided on the front edge, in which the robot apparatus is made to perform work of gripping a target object conveyed on a conveyer. Specifically, the technology described in Patent Literature 1 stores in advance a first tool position in a state of the gripping mechanism gripping the target object, a second tool position in a state of the gripping mechanism releasing the target object and moving to a designated position, and the coordinates of a characteristic part of the target object extracted from an image captured by the imaging means at the second tool position. Subsequently, when performing work, the gripping mechanism is made to move from the second tool position to the first tool position and grip the target object so that the coordinates of the characteristic part of the target object being transported match the coordinates stored in advance.